Manual Park Release Mechanism for Power-Loss Vehicle Locking

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Solution Overview

Problem

Existing park lock release arrangements in vehicles require manual access underneath the vehicle to release the transmission from park mode, posing safety risks due to potential vehicle movement during power failures, and existing electric park brakes can become immobilized without power.

Innovation Solution

A power actuated park system with a rotatable selector shaft that can be manually switched to a release mode using a locking pin member, allowing the selector shaft to be locked in the release position without requiring the same motion for release, reducing the risk of unintentional locking and enabling easy re-engagement of the park mode if the vehicle moves unexpectedly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a bolt is screwed through a bracket to rotate the selector shaft lever to release the transmission from park mode, then the transmission can be released from park mode, but the person manipulating the bolt must crawl underneath the vehicle which poses safety risks due to potential vehicle movement

Engineering Contradiction:

Improveaccessibility of release mechanismVSAvoidsafety risk from vehicle movement

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The release mechanism is extracted from the under-vehicle location and repositioned to be accessible from the cabin area. The selector shaft lever is coupled to a release mechanism that can be actuated from within the vehicle, removing the need for personnel to position themselves underneath the vehicle and thereby eliminating the safety hazard associated with potential vehicle movement during the release operation.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the selector shaft is spring loaded to automatically return to park mode position, then the transmission automatically engages park mode when released, but the person manipulating the release mechanism must quickly unscrew the bolt to arrest vehicle movement before injury occurs

Engineering Contradiction:

Improveautomatic park mode re-engagementVSAvoidtime required to unscrew bolt

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The manual bolt-screwing mechanism is replaced with a lever-based mechanical system. The selector shaft lever can be manually rotated to the release position and held there using a retaining member, eliminating the need for rapid bolt manipulation. The spring-loaded automatic return to park mode is preserved, providing reliable automatic re-engagement without requiring the operator to quickly unscrew a bolt to arrest vehicle movement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Extent of automation

If electric motor or hydraulic fluid pressure is used to rotate the shaft for park brake deployment, then the park brake can be deployed automatically, but the vehicle becomes immobilized if electrical power or hydraulic fluid pressure is not available

Engineering Contradiction:

Improveautomatic park brake deploymentVSAvoidoperability without power

Core Design Contradiction:

Extent of automationVSAdaptability or versatility

Solution Approach 1:

The system incorporates a manual release mechanism that can be activated in advance or as a backup when power is unavailable. The selector shaft lever can be manually rotated to the release position and held there using a retaining member, ensuring the vehicle can be released from park mode even when electrical power or hydraulic fluid pressure is not available, thus maintaining operability under all conditions.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If a locking pin member is inserted into an aperture to lock the selector shaft in release mode position, then the selector shaft can be securely locked in release mode position, but the device complexity increases

Engineering Contradiction:

Improvelocking reliabilityVSAvoidnumber of locking components

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking function is segmented into distinct components: the selector shaft lever for rotation, the retaining member for holding the release position, and the spring-loaded mechanism for automatic return. This segmentation allows each component to perform its specific function efficiently while maintaining overall system reliability. The retaining member works in conjunction with the spring mechanism to provide secure locking without requiring complex multi-component locking systems.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2825797B1Park release method and vehicle having park release means

Publication Date: 2021.05.12 JAGUAR LAND ROVER LTD

Figure 1(a)~1(c)
Figure 2(a)~2(b)
Figure 3

AI summary

In one aspect of the invention there is provided a method of manually releasing power actuated vehicle park means in the absence of power, the method comprising the steps of: rotating a power actuated selector shaft from a park mode position in which one or more wheels are locked by the park means to a park release mode position in which the one or more wheels are released by the park means; and locking the selector shaft in the release mode position by means of locking means, whereby the successive steps of rotating the selector shaft to the release mode position and subsequently locking the selector shaft in the release mode position comprise manual translation or rotation of one or more members in first and second directions respectively, the first direction being different from the second direction.